Washington (CNN) - Sen. Robert Menendez's office issued a statement Wednesday saying he had traveled several times on a plane belonging to a Florida eye doctor who had given political donations to Menendez but that all the trips were "paid for and reported appropriately." The office also denied allegations the New Jersey Democrat had engaged the services of prostitutes.

The statement was issued after FBI agents searched the West Palm Beach office of the ophthalmologist, Dr. Salomon Melgen. Investigators were seen carrying out boxes during the search, which began Tuesday night and continued into Wednesday. An FBI spokesman in Florida confirmed there was "law enforcement activity" at the location where the search occurred but did not mention Melgen or anyone else and did not explain what agents were investigating.